Radiological Case of the Month

A 2-year-old boy was examined for increasing head size after a fall that had occurred one month earlier. No associated neurologic findings were detected. The anterior fontanelle was open but tense. The optic fundi showed no papilledema. Results of routine blood and urine laboratory examinations were normal. A computed tomographic examination of the head was part of the investigation of the etiology of macrocrania (Figs 1 to 3).

Denouement and Discussion 

Suprasellar Arachnoid Cyst  Congenital arachnoid cysts may occur in a variety of intracranial sites, but a suprasellar location is rare. Nearly 70 published cases of suprasellar arachnoid cysts were found in a literature review.^1-3Seventy-five percent to 90% of patients with congenital subarachnoid cysts present with hydrocephalus in infancy or early childhood.¹ Older patients may present with headaches and hypopituitarism. Associated macrocrania is present in approximately 50% of patients,¹ while impaired visual acuity and/or abnormal visual fields are found in 25%.¹